Read from BufferReleaseChannel in background thread (7c9fa270) · Commits · e / os / android_frameworks_native

libs/gui/BLASTBufferQueue.cpp

+151 −10

Original line number	Diff line number	Diff line
		@@ -22,11 +22,14 @@

		#include <com_android_graphics_libgui_flags.h>
		#include <cutils/atomic.h>
		#include <ftl/fake_guard.h>
		#include <gui/BLASTBufferQueue.h>
		#include <gui/BufferItemConsumer.h>
		#include <gui/BufferQueueConsumer.h>
		#include <gui/BufferQueueCore.h>
		#include <gui/BufferQueueProducer.h>
		#include <sys/epoll.h>
		#include <sys/eventfd.h>

		#include <gui/FrameRateUtils.h>
		#include <gui/GLConsumer.h>
		@@ -74,6 +77,12 @@ namespace android {
		std::unique_lock _lock{mutex}; \
		base::ScopedLockAssertion assumeLocked(mutex);

		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		static ReleaseBufferCallback EMPTY_RELEASE_CALLBACK =
		[](const ReleaseCallbackId&, const sp<Fence>& /releaseFence/,
		std::optional<uint32_t> /currentMaxAcquiredBufferCount/) {};
		#endif

		void BLASTBufferItemConsumer::onDisconnect() {
		Mutex::Autolock lock(mMutex);
		mPreviouslyConnected = mCurrentlyConnected;
		@@ -215,6 +224,12 @@ BLASTBufferQueue::BLASTBufferQueue(const std::string& name, bool updateDestinati
		},
		this);

		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		std::unique_ptr<gui::BufferReleaseChannel::ConsumerEndpoint> bufferReleaseConsumer;
		gui::BufferReleaseChannel::open(mName, bufferReleaseConsumer, mBufferReleaseProducer);
		mBufferReleaseReader = std::make_shared<BufferReleaseReader>(std::move(bufferReleaseConsumer));
		#endif

		BQA_LOGV("BLASTBufferQueue created");
		}

		@@ -244,6 +259,9 @@ BLASTBufferQueue::~BLASTBufferQueue() {
		void BLASTBufferQueue::onFirstRef() {
		// safe default, most producers are expected to override this
		mProducer->setMaxDequeuedBufferCount(2);
		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		mBufferReleaseThread.start(sp<BLASTBufferQueue>::fromExisting(this));
		#endif
		}

		void BLASTBufferQueue::update(const sp<SurfaceControl>& surface, uint32_t width, uint32_t height,
		@@ -269,6 +287,9 @@ void BLASTBufferQueue::update(const sp<SurfaceControl>& surface, uint32_t width,
		if (surfaceControlChanged) {
		t.setFlags(mSurfaceControl, layer_state_t::eEnableBackpressure,
		layer_state_t::eEnableBackpressure);
		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		t.setBufferReleaseChannel(mSurfaceControl, mBufferReleaseProducer);
		#endif
		applyTransaction = true;
		}
		mTransformHint = mSurfaceControl->getTransformHint();
		@@ -386,6 +407,7 @@ void BLASTBufferQueue::transactionCallback(nsecs_t /latchTime/, const sp<Fence
		stat.latchTime,
		stat.frameEventStats.dequeueReadyTime);
		}
		#if !COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		auto currFrameNumber = stat.frameEventStats.frameNumber;
		std::vector<ReleaseCallbackId> staleReleases;
		for (const auto& [key, value]: mSubmitted) {
		@@ -401,6 +423,7 @@ void BLASTBufferQueue::transactionCallback(nsecs_t /latchTime/, const sp<Fence
		stat.currentMaxAcquiredBufferCount,
		true /* fakeRelease */);
		}
		#endif
		} else {
		BQA_LOGE("Failed to find matching SurfaceControl in transactionCallback");
		}
		@@ -411,6 +434,15 @@ void BLASTBufferQueue::transactionCallback(nsecs_t /latchTime/, const sp<Fence
		}
		}

		void BLASTBufferQueue::flushShadowQueue() {
		BQA_LOGV("flushShadowQueue");
		int numFramesToFlush = mNumFrameAvailable;
		while (numFramesToFlush > 0) {
		acquireNextBufferLocked(std::nullopt);
		numFramesToFlush--;
		}
		}

		// Unlike transactionCallbackThunk the release buffer callback does not extend the life of the
		// BBQ. This is because if the BBQ is destroyed, then the buffers will be released by the client.
		// So we pass in a weak pointer to the BBQ and if it still alive, then we release the buffer.
		@@ -428,15 +460,6 @@ ReleaseBufferCallback BLASTBufferQueue::makeReleaseBufferCallbackThunk() {
		};
		}

		void BLASTBufferQueue::flushShadowQueue() {
		BQA_LOGV("flushShadowQueue");
		int numFramesToFlush = mNumFrameAvailable;
		while (numFramesToFlush > 0) {
		acquireNextBufferLocked(std::nullopt);
		numFramesToFlush--;
		}
		}

		void BLASTBufferQueue::releaseBufferCallback(
		const ReleaseCallbackId& id, const sp<Fence>& releaseFence,
		std::optional<uint32_t> currentMaxAcquiredBufferCount) {
		@@ -611,7 +634,12 @@ status_t BLASTBufferQueue::acquireNextBufferLocked(
		bufferItem.mGraphicBuffer->getHeight(), bufferItem.mTransform,
		bufferItem.mScalingMode, crop);

		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		ReleaseBufferCallback releaseBufferCallback =
		applyTransaction ? EMPTY_RELEASE_CALLBACK : makeReleaseBufferCallbackThunk();
		#else
		auto releaseBufferCallback = makeReleaseBufferCallbackThunk();
		#endif
		sp<Fence> fence = bufferItem.mFence ? new Fence(bufferItem.mFence->dup()) : Fence::NO_FENCE;

		nsecs_t dequeueTime = -1;
		@@ -1224,7 +1252,120 @@ bool BLASTBufferQueue::isSameSurfaceControl(const sp<SurfaceControl>& surfaceCon
		void BLASTBufferQueue::setTransactionHangCallback(
		std::function<void(const std::string&)> callback) {
		std::lock_guard _lock{mMutex};
		mTransactionHangCallback = callback;
		mTransactionHangCallback = std::move(callback);
		}

		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)

		BLASTBufferQueue::BufferReleaseReader::BufferReleaseReader(
		std::unique_ptr<gui::BufferReleaseChannel::ConsumerEndpoint> endpoint)
		: mEndpoint{std::move(endpoint)} {
		mEpollFd = android::base::unique_fd{epoll_create1(0)};
		LOG_ALWAYS_FATAL_IF(!mEpollFd.ok(),
		"Failed to create buffer release epoll file descriptor. errno=%d "
		"message='%s'",
		errno, strerror(errno));

		epoll_event registerEndpointFd{};
		registerEndpointFd.events = EPOLLIN;
		registerEndpointFd.data.fd = mEndpoint->getFd();
		status_t status =
		epoll_ctl(mEpollFd.get(), EPOLL_CTL_ADD, mEndpoint->getFd(), &registerEndpointFd);
		LOG_ALWAYS_FATAL_IF(status == -1,
		"Failed to register buffer release consumer file descriptor with epoll. "
		"errno=%d message='%s'",
		errno, strerror(errno));

		mEventFd = android::base::unique_fd(eventfd(0, EFD_CLOEXEC \| EFD_NONBLOCK));
		LOG_ALWAYS_FATAL_IF(!mEventFd.ok(),
		"Failed to create buffer release event file descriptor. errno=%d "
		"message='%s'",
		errno, strerror(errno));

		epoll_event registerEventFd{};
		registerEventFd.events = EPOLLIN;
		registerEventFd.data.fd = mEventFd.get();
		status = epoll_ctl(mEpollFd.get(), EPOLL_CTL_ADD, mEventFd.get(), &registerEventFd);
		LOG_ALWAYS_FATAL_IF(status == -1,
		"Failed to register buffer release event file descriptor with epoll. "
		"errno=%d message='%s'",
		errno, strerror(errno));
		}

		BLASTBufferQueue::BufferReleaseReader& BLASTBufferQueue::BufferReleaseReader::operator=(
		BufferReleaseReader&& other) {
		if (this != &other) {
		ftl::FakeGuard guard{mMutex};
		ftl::FakeGuard otherGuard{other.mMutex};
		mEndpoint = std::move(other.mEndpoint);
		mEpollFd = std::move(other.mEpollFd);
		mEventFd = std::move(other.mEventFd);
		}
		return *this;
		}

		status_t BLASTBufferQueue::BufferReleaseReader::readBlocking(ReleaseCallbackId& outId,
		sp<Fence>& outFence,
		uint32_t& outMaxAcquiredBufferCount) {
		epoll_event event{};
		while (true) {
		int eventCount = epoll_wait(mEpollFd.get(), &event, 1 /* maxevents /, -1 / timeout */);
		if (eventCount == 1) {
		break;
		}
		if (eventCount == -1 && errno != EINTR) {
		ALOGE("epoll_wait error while waiting for buffer release. errno=%d message='%s'", errno,
		strerror(errno));
		}
		}

		if (event.data.fd == mEventFd.get()) {
		uint64_t value;
		if (read(mEventFd.get(), &value, sizeof(uint64_t)) == -1 && errno != EWOULDBLOCK) {
		ALOGE("error while reading from eventfd. errno=%d message='%s'", errno,
		strerror(errno));
		}
		return WOULD_BLOCK;
		}

		std::lock_guard lock{mMutex};
		return mEndpoint->readReleaseFence(outId, outFence, outMaxAcquiredBufferCount);
		}

		void BLASTBufferQueue::BufferReleaseReader::interruptBlockingRead() {
		uint64_t value = 1;
		if (write(mEventFd.get(), &value, sizeof(uint64_t)) == -1) {
		ALOGE("failed to notify dequeue event. errno=%d message='%s'", errno, strerror(errno));
		}
		}

		void BLASTBufferQueue::BufferReleaseThread::start(const sp<BLASTBufferQueue>& bbq) {
		mRunning = std::make_shared<std::atomic_bool>(true);
		mReader = bbq->mBufferReleaseReader;
		std::thread([running = mRunning, reader = mReader, weakBbq = wp<BLASTBufferQueue>(bbq)]() {
		pthread_setname_np(pthread_self(), "BufferReleaseThread");
		while (*running) {
		ReleaseCallbackId id;
		sp<Fence> fence;
		uint32_t maxAcquiredBufferCount;
		if (status_t status = reader->readBlocking(id, fence, maxAcquiredBufferCount);
		status != OK) {
		continue;
		}
		sp<BLASTBufferQueue> bbq = weakBbq.promote();
		if (!bbq) {
		return;
		}
		bbq->releaseBufferCallback(id, fence, maxAcquiredBufferCount);
		}
		}).detach();
		}

		BLASTBufferQueue::BufferReleaseThread::~BufferReleaseThread() {
		*mRunning = false;
		mReader->interruptBlockingRead();
		}

		#endif

		} // namespace android

libs/gui/include/gui/BLASTBufferQueue.h

+45 −0

Original line number	Diff line number	Diff line
		@@ -315,6 +315,51 @@ private:
		std::function<void(const std::string&)> mTransactionHangCallback;

		std::unordered_set<uint64_t> mSyncedFrameNumbers GUARDED_BY(mMutex);

		#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
		class BufferReleaseReader {
		public:
		BufferReleaseReader() = default;
		BufferReleaseReader(std::unique_ptr<gui::BufferReleaseChannel::ConsumerEndpoint>);
		BufferReleaseReader& operator=(BufferReleaseReader&&);

		// Block until we can read a buffer release message.
		//
		// Returns:
		// * OK if a ReleaseCallbackId and Fence were successfully read.
		// * WOULD_BLOCK if the blocking read was interrupted by interruptBlockingRead.
		// * UNKNOWN_ERROR if something went wrong.
		status_t readBlocking(ReleaseCallbackId& outId, sp<Fence>& outReleaseFence,
		uint32_t& outMaxAcquiredBufferCount);

		// Signals the reader's eventfd to wake up any threads waiting on readBlocking.
		void interruptBlockingRead();

		private:
		std::mutex mMutex;
		std::unique_ptr<gui::BufferReleaseChannel::ConsumerEndpoint> mEndpoint GUARDED_BY(mMutex);
		android::base::unique_fd mEpollFd;
		android::base::unique_fd mEventFd;
		};

		// BufferReleaseChannel is used to communicate buffer releases from SurfaceFlinger to
		// the client. See BBQBufferQueueProducer::dequeueBuffer for details.
		std::shared_ptr<BufferReleaseReader> mBufferReleaseReader;
		std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint> mBufferReleaseProducer;

		class BufferReleaseThread {
		public:
		BufferReleaseThread() = default;
		~BufferReleaseThread();
		void start(const sp<BLASTBufferQueue>&);

		private:
		std::shared_ptr<std::atomic_bool> mRunning;
		std::shared_ptr<BufferReleaseReader> mReader;
		};

		BufferReleaseThread mBufferReleaseThread;
		#endif
		};

		} // namespace android

services/surfaceflinger/Layer.cpp

+19 −4

Original line number	Diff line number	Diff line
		@@ -1951,15 +1951,24 @@ bool Layer::setDropInputMode(gui::DropInputMode mode) {
		void Layer::callReleaseBufferCallback(const sp<ITransactionCompletedListener>& listener,
		const sp<GraphicBuffer>& buffer, uint64_t framenumber,
		const sp<Fence>& releaseFence) {
		if (!listener) {
		if (!listener && !mBufferReleaseChannel) {
		return;
		}

		SFTRACE_FORMAT_INSTANT("callReleaseBufferCallback %s - %" PRIu64, getDebugName(), framenumber);

		ReleaseCallbackId callbackId{buffer->getId(), framenumber};
		const sp<Fence>& fence = releaseFence ? releaseFence : Fence::NO_FENCE;
		uint32_t currentMaxAcquiredBufferCount =
		mFlinger->getMaxAcquiredBufferCountForCurrentRefreshRate(mOwnerUid);
		listener->onReleaseBuffer({buffer->getId(), framenumber},
		releaseFence ? releaseFence : Fence::NO_FENCE,
		currentMaxAcquiredBufferCount);

		if (listener) {
		listener->onReleaseBuffer(callbackId, fence, currentMaxAcquiredBufferCount);
		}

		if (mBufferReleaseChannel) {
		mBufferReleaseChannel->writeReleaseFence(callbackId, fence, currentMaxAcquiredBufferCount);
		}
		}

		sp<CallbackHandle> Layer::findCallbackHandle() {
		@@ -2077,6 +2086,7 @@ void Layer::onLayerDisplayed(ftl::SharedFuture<FenceResult> futureFenceResult,

		void Layer::releasePendingBuffer(nsecs_t dequeueReadyTime) {
		for (const auto& handle : mDrawingState.callbackHandles) {
		handle->bufferReleaseChannel = mBufferReleaseChannel;
		handle->transformHint = mTransformHint;
		handle->dequeueReadyTime = dequeueReadyTime;
		handle->currentMaxAcquiredBufferCount =
		@@ -3508,6 +3518,11 @@ bool Layer::setTrustedPresentationInfo(TrustedPresentationThresholds const& thre
		return haveTrustedPresentationListener;
		}

		void Layer::setBufferReleaseChannel(
		const std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint>& channel) {
		mBufferReleaseChannel = channel;
		}

		void Layer::updateLastLatchTime(nsecs_t latchTime) {
		mLastLatchTime = latchTime;
		}

services/surfaceflinger/Layer.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -537,6 +537,7 @@ public:
		};

		BufferInfo mBufferInfo;
		std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint> mBufferReleaseChannel;

		// implements compositionengine::LayerFE
		const compositionengine::LayerFECompositionState* getCompositionState() const;
		@@ -724,6 +725,8 @@ public:

		bool setTrustedPresentationInfo(TrustedPresentationThresholds const& thresholds,
		TrustedPresentationListener const& listener);
		void setBufferReleaseChannel(
		const std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint>& channel);

		// Creates a new handle each time, so we only expect
		// this to be called once.

services/surfaceflinger/SurfaceFlinger.cpp

+4 −0

Original line number	Diff line number	Diff line
		@@ -5063,6 +5063,10 @@ uint32_t SurfaceFlinger::updateLayerCallbacksAndStats(const FrameTimelineInfo& f
		}
		}

		if (what & layer_state_t::eBufferReleaseChannelChanged) {
		layer->setBufferReleaseChannel(s.bufferReleaseChannel);
		}

		const auto& requestedLayerState = mLayerLifecycleManager.getLayerFromId(layer->getSequence());
		bool willPresentCurrentTransaction = requestedLayerState &&
		(requestedLayerState->hasReadyFrame() \|\|